This disclosure relates to a cold air buffer supply tube for a gas turbine engine.
A gas turbine engine includes a compressor section, a combustion section, and a diffuser positioned downstream of the compressor section and near a beginning of the combustion section. A cold air buffer supply tube is used to direct cooling air from an air supply through the diffuser housing and into a bearing compartment. The cold air buffer supply tube includes a tube body with a first fitting at one end that is coupled to an external tube, and a second fitting at an opposite end. The second fitting includes a nut, washer, and nipple that are secured to the tube body.
A baffle is welded to an opening formed within a bearing housing that defines the bearing compartment. The cold air buffer supply tube is then inserted through the baffle to direct air into the bearing compartment. Air flows out of a single tip opening formed in the nipple.
The current cold air buffer supply tube is comprised of a significant number of parts, which can be difficult and time consuming to assemble. Further, the baffle can break loose from the bearing housing, potentially damaging buffer shields located nearby. Once a baffle has broken loose, there is potential for leakage of hot air into a bearing cooling system, which could adversely affect bearing life. Also, under certain conditions, the tube coupling nut can back off, subsequently damaging the tube, and again potentially opening a leak path for hot air.
Accordingly, there is a need to provide a lubrication system that can precisely lubricate the bearings and seal plate, as well as addressing the other short comings discussed above.